71 Mach 1,trans swap ,C6 to Toploader

Meinrotti

New Member
May 16, 2010
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WA.
Hi ,I am new to this forum, so I was wondering if anyone could tell me if there is a difference between the auto/manual transmission drivelines. I have a 71 Mach 1 351 4v and I have started to change from a C-6 to a toploader and have to acquire a drive shaft . I was wondering what to look for as well as the length needed . Also any info on toploader yokes would be appreciated. There are plenty of yokes on ebay ,I am unsure as to which one I should look for .Thanks
 
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It depends on the Toploader you bought. There's two basic verisons--- big block and small block, along with different tailshaft lengths. The big block version uses the same yoke as your C6 does----31 spline. The small block uses a 28 spline. The C-6 is tail is longer than the Mustang/Fairlane Toploaders by 3 inches.
 
You may need to wait and measure for the correct driveshaft length in case there are unforeseen variables. Driveshaft length will depend on what length tailhousing you are using AND what yoke is on the 9" rear. The correct Mustang toploader for a 351 uses a tailshaft that is 14" in length and a 28 spline output shaft. All cases are 10" so that is not a problem (unless you found an early 64 narrow case which is also 10" but will not bolt to the back of your 351 using a stock bell housing.)

The 28 spline output shaft use the same splined yoke as a C4 Automatic. The 31 spline output shaft uses the same splined yoke as the C6. In either case, you need to know what type of U joint you want to use (1310, 1330, or 1350) with the driveshaft. The higher the #, the stronger the joint and you should use at least a 1330 style with a toploader. You must match the joint to what the yoke and driveshaft was originally built for although it is possible to match up different combinations, such as using a 1330 yoke on a 1310 driveshaft (or vice versa) through special conversion U joints.